Plumbing!

**Russ** · 14-12-2005, 12:14

I've got a combi-boiler.

Anyone have any idea why, if I keep the hot water on for about an hour, the water coming out of the hot tap when I run a bath is little more than a trickle?

Other times when I keep it on for an hour or so (or even longer), the hot water comes out at a good rate but is little more than lukewarm.

It's really annoying and sometimes running a bath takes ages.

14-12-2005, 12:44

I'm confused, Russ, what do you mean about 'keeping the water on for an hour'? - our combi boiler heats the water as you use it - keeping it on for an hour would overflow the bath??

Xaccers · 14-12-2005, 12:51

Russ, does your combi have a hot water storage tank as well? (ours does, but my old one didn't)

etccarmageddon · 14-12-2005, 13:15

some combis within the combi boiler itself have a small tank inside - these are the good ones which is to ensure the water is at a stable temperature.

not sure what you mean by having it on for an hour Russ?

perhaps your heating is competing for the boiler - try it with the heating turned off and see if that makes a difference.

jellybaby · 14-12-2005, 13:37

Also ensure that the pressure on the boiler hasn't dropped. Mine sometimes drops and this affects the water temperature (goes up and down). I think it should be about 1.5 bar, but not more than 2

---------- Post added at 13:37 ---------- Previous post was at 13:30 ----------

just found this

Quote:

Combination boilers have a pressure gauge which shows the water pressure in the system. The pressure in the system when cold is typically around 1 bar but your Installer should tell you the expected figure. The pressure will obviously rise when the system is hot but should not rise too much or anywhere near 3 bar pressure.

from http://www.gas-news.co.uk/consumerscombiuser.htm

etccarmageddon · 14-12-2005, 13:44

that's right - check the pressure guage. you should have a small tap near it which you can open up to repressure the system - you open the tap and let pressure rise until it gets to around 1 bar.

**Graham M** · 14-12-2005, 13:52

I always thought that the pressure was for the heating system?

Wicked_and_Crazy · 14-12-2005, 13:54

Quote:

Originally Posted by Russ D

It's really annoying and sometimes running a bath takes ages.

You should only use enough to cover your vegetables

ellie · 14-12-2005, 13:57

Quote:

Originally Posted by Wicked_and_Crazy

You should only use enough to cover your vegetables

Probably wont need much then

**Russ** · 14-12-2005, 15:13

Quote:

Originally Posted by homealone

I'm confused, Russ, what do you mean about 'keeping the water on for an hour'? - our combi boiler heats the water as you use it - keeping it on for an hour would overflow the bath??

Sorry - it's not a combi

I have to set my boiler for the water to heat up for about half an hour before it's warm/hot enough for a bath.

Sometimes when it's hot enough, it only comes out as a trickle, other times no matter how long it's been on for, it comes out a bit faster but is only slightly warm.

goldoni · 14-12-2005, 15:21

Most combi boilers can deal with 9.5lt per min, but the other thing is temperature rise, which is normally about 49 deg.

With these two facts we have one more, the flow of the tap ie your kitchen tap will normally give a lower flow rate than your bath tap which is geared for about 15lt per min so if you slow it down so it is in spec ie 9.lt per min you should get nice hot water at about 60 deg, but it could take some time.

The combi boilers that have a storage tank is good for hand washing but not for running a bath.

The pressure dial normally should be at about 1.5bar but this will not effect the flow of the hot water, it could just lock the boiler if the pressure drops to 0,,,this would happen if you say bleed the radiators.

One problem with combi boilers is the gas flow, if you don’t put it in you can’t get it out so the gas feed pipe should be 22mm with the last part in 15mm. If you gas pipe is run mostly in 15mm this will need to be corrected.

Hope this helps

Well scrap that then,,,

Check the tanks in your loft, do you have any or do you have a sealed system

Halcyon · 14-12-2005, 15:23

I have this problem too. And if I want a really hot bath I have to leave it for ages to fill up as it will be a trickle and not a normal flow.
Not sure what on earccauses this, but it can be annoying.
May be its because I no longer have a tank in the bathroom and it has to be pumped up stairs, I dont know.

**Graham M** · 14-12-2005, 15:24

Quote:

Originally Posted by goldoni

Hope this helps

Hehe it doesn't, read Russ' post just before yours

goldoni · 14-12-2005, 15:37

Quote:

Originally Posted by Zeph

Quote:

Originally Posted by goldoni

Hope this helps

Hehe it doesn't, read Russ' post just before yours

Did see it after I posted

but with this info Russ has two problems,,,,,

Nugget · 14-12-2005, 15:39

Quote:

Originally Posted by goldoni

Did see it after I posted

but with this info Russ has two problems,,,,,

Trust me - Russ has got far more than 2 problems